The present invention relates to a printed-circuit board module of the type in which a printed-wiring board has mounted thereon a smaller printed-circuit board with parts mounted thereon. The "printed-circuit board" mentioned herein is intended as a generic term for a printed-wiring board having a rigid board as of glass epoxy and a flexible printed-circuit sheet having a flexible sheet as of polyimide.
FIG. 4 depicts an example of a conventional printed-circuit board module of this kind. The illustrated example is what is called a board-to-board type module with a printed-wiring board 11 having mounted thereon a smaller printed-wiring board 12.
The printed-wiring board 11 has an opening 13, in which parts (not shown) mounted on the underside of the printed-wiring board 12 are held upside down.
The printed-wiring boards 11 and 12 are electrically connected via pin terminals 14 secured at one ends thereof to the printed-wiring board 12 in side by side relation on the two opposite sides of the printed-wiring board 12. The pin terminals 14 have their other ends bent as required and connected by soldering to connecting conductor pattern lands 15 formed side by side on the printed-wiring board 11. Printed wiring patterns connected the connecting conductor pattern lands 15 are not shown.
The pin terminals 14 thus provide electrical and mechanical connections between the printed-wiring boards 11 and 12.
As described above, the conventional printed-circuit board module uses the pin terminals 14 to establish electrical connections between the printed-wiring boards 11 and 12; therefore, its fabrication involves cumbersome securing of the pin terminals 15 to the printed-wiring board 12 and their manual soldering to the conductor pattern lands 15, and hence it requires a large number of man-hours.
Moreover, since the pin terminals 14 mechanically supporting the printed-wiring board 12 are thin and apt to bend, the board 12 cannot stably be held at a predetermined position (or height).
Furthermore, in this kind of printed-circuit board module it is generally required that the parts mounted on the underside of the printed-wiring board 12 held in the opening 13 do not extend downwardly of the underside of the printed-wiring board 11. Accordingly, there are cases where the lengths and bending of the pin terminals 14 need to be adjusted according to the heights of the parts mounted on the underside of the printed-wiring board 12; and such adjustments of the pin terminals 14 are not easy and are troublesome.